Field: The instant invention relates to systems for irrigating land by a long wheel-supported conduit or pipe which may be moved over the land to be irrigated. The invention particularly relates to an automated system which automatically couples to a riser and automatically moves from one riser to the next and which automatically sprinkles for a proper period of time.
Prior Art: Sprinkler irrigation systems for large farms fall into two general catagories: pivot and linear systems. The pivot sprinklers are anchored at one end with the sprinkler line rotating about the anchor, sprinkling a circular area. Linear sprinklers comprise two general types: wheel move and line move systems.
The wheel move sprinklers dominate commercially. The wheel move sprinklers do not move while sprinkling and have wheels which are rigidly fixed to the central conduit, i.e., the central conduit forms the axle to which the large wheels are attached. The unit is moved by a motorized prime mover generally located midway between ends of the conduit. The wheel move systems in present commercial use require considerable attention since the moving, timing of the sprinkling operation and connection of the lateral to a riser along the main supply line are all manual operations. The lateral pipeline, that is the central conduit with wheels rigidly affixed thereto, is generally manually connected by a telescoping section or a flexible hose to a main supply line running along one side of a field. The lateral is generally one quarter mile or more in length.
Manual operation of a wheel move involves positioning the lateral pipeline so that the sprinkling heads are all substantially vertical, hooking the telescoping pipe or flexible hose attached to one end of the central conduit to a riser from the main water supply line, which is generally buried. The riser valve is opened and the stationary pipeline sprinkles an area about 40 to 80 feet wide along its length. After the sprinkling has continued for a sufficient time, the apparatus must be moved by having the operator shut off the water, open the drain valve in the central conduit, wait for the conduit to drain, disconnect the system from the main supply, walk to the center of the field and start the prime mover. The apparatus is then moved approximately alongside the next riser and the operation repeated.
Efficient irrigation of many fields requires that the sprinklers be moved about every few hours over the entire 24 hours of a day. This drastically interferes with a farmer's other chores and sleep. Therefore, most manual wheel move systems are not operated at optimum conditions but at the farmer's convenience, causing inadequate irrigation at times and a wasting of water and over-watering at other times.
The wheel move is substantially less expensive than intermittent or continuous line move systems having tall towers along the lateral which are each self-propelled, or the pivot type sprinklers which also have tall towers. However, because of the manual operation required for wheel moves, many farmers use the more expensive pivot type sprinklers (which fail to irrigate the corners of square fields) because the pivot type sprinklers are substantially automatic and require minimum attention.
Although the desirability of an automatic wheel move system has been recognized for some time, the achievement of a commercially acceptable system has not been accomplished before now. One automated wheel move system is illustrated in the Imeson Patent, U.S. Pat. No. 3,575,200 which discloses a central, self-propelled vehicle having valve attachment means. The vehicle rides along the pipe, that is it straddles the pipe, which has been laid down the center of a field. The vehicle uses a main supply pipe as a guide and is rigidly attached to a pair of laterals extending on each side of the vehicle.
A number of other patents relate to automated controls for line move systems, that is systems which use tall self-propelled towers. In U.S. Pat. No. 3,444,941 to Purtell, a line move system which intermittently irrigates a field is disclosed. A tall trolley travels along the main supply line and is fixed to the lateral line move system by a flexible hose. The trolley rides along the pipe and has a winch to power itself along a fixed cable. Another system is disclosed in Stafford Reissue Patent 26,285, which utilizes a telescoping pipe parallel to the main supply line so that the lateral may move down the field while connected to one riser, then stop after it has passed the riser in front of the riser to which it is attached, permitting the telescoping section to retract and attach to the new riser and proceed down the field.
The patent to Cornelius, U.S. Pat. No. 3,583,428, relates to a line move system which has a tractor-like device which drags a long main supply hose behind it as the system moves down the field. The Clemmins device, U.S. Pat. No. 3,707,164 is an automatic sprinkler device which moves continuously down a field while picking up water from an irrigation ditch. This device requires very level fields so that the ditch may have the proper slight drop. The patent to Rodgers, U.S. Pat. No. 3,463,175, discloses a device which moves along a rail and is attached by flexible hose to a line move system.
U.S. Pat. No. 3,929,197 to Malott and Erath shows a remote end control for the prime mover of a wheel move system. The control is manually actuated by the user while standing at one end of the lateral pipeline.